Slipper vane and valve combination for vane-type fluid pump

ABSTRACT

A pump vane embodies a shoe of broad area and pivotally linked to its rotor to follow the internal cam surface of a pump cylinder with an effective sealing action and a balanced pumping action.

United States Patent Fox Mar. 7, 1972 [54] SLIPPER VANE AND VALVE 745,755 12/1903 Allen ..418/147 COMBINATION FDR VANE.TYPE 830,334 9/1906 Kummerow ..4l8/l47 X 3,099,964 8/ 1963 Eickmann ..418/147 FLUID PUMP 3,415,197 12/1968 Eickmann.... .....418/148 [72] Inventor: Leonard N. Fox, Glendale, Calif. 2,333,323 11/1943 Livermore .....418/268 Assigneez Crane Co. Burbank Calif 3,110,266 1 1/ 1963 Lrvermore ..418/234 [22] Filed: May 25 1970 FOREIGN PATENTS OR APPLICATIONS [211 App. No.: 40,076 24,388 6/1931 Netherlands ..4l8/145 Primary Examiner-Carlton R. Croyle [52] [1.8. CI ..4l8/136, 418/147, 418/224 Assistant Examiner-John .1. Vrablik [51] Int. Cl ..F0lc 19/00, F03c 3/00, F04c 27/00 Attorney-Lynn'I-l. Latta [58] Field ofSearch ..418/136,145,147,148,225,

418/234, 236, 260, 146, 189, 224, 268; 417/284, [57] ABSTRACT 310 A pump vane embodies a shoe of broad area and pivotally linked to its rotor to follow the internal cam surface of a pump [56] References Cited cylinder with an effective sealing action and a balanced pump- UNITED STATES PATENTS 8 action- 348,879 9/1886 Austin ..418/147 X 12 Claims, 4 Drawing Figures PATENTEDMAR 7 I972 If; VEN TOR.

[em/A20 MPOz viva/mur- I SLIPPER VANE AND VALVE COMBINATION FOR VANE- TYPE FLUID PUMP BACKGROUND OF THE INVENTION Existing vane pumps utilize close-fitting vanes sliding radially in rotor slots which prevent the vanes from aligning with the internal cam surface of the cylinder and thus require a relatively small vane tip radius resulting in poor lubrication. A slipper pump having blades of semicircular cross section reciprocating radially in pockets in a rotor with a fluid displacement action while following the out-of-round internal surface of a housing stator, is disclosed in Rhine US. Pat. No. 2,628,568. US. Pat. No. 2,333,323 and 1,495,526 show similar pumps.

SUMMARY OF THE INVENTION My improved slipper vane combines a radially sliding valve of leaf form having an outer margin pivotally coupled to a slipper or shoe having an outer face of broad area and convexly rounded contour in sliding contact with the internal cam surface of the pump cylinder. The shoe is retained in a socket in the rotor against circumferential displacement relative to the rotor, and is pivotal on the outer margin of the valve so as to tilt to conform to the slope of the cam surface of the cylinder. Among the objects of the invention are to provide a pump vane:

1. Having a rounded vane tip bearing face of large radius such as to follow and substantially conform to the irregular cam' surface of a pumping cylinder so as to provide and effective seal;

2. Having a bearing face with large area such as to distribute frictional loading and minimize wear;

3. Operating with improved lubrication of the vane tip bearing face;

4. Having reduced sensitivity to contamination;

5. Permitting wider manufacturing tolerances;

6. Having a fluid displacement (pumping) operation in moving radially in a socket in a carrying rotor, and having an improved valve action in such pumping operation;

7. Combined with improved rotor and cylinder components in a pump assembly of improved operation.

DESCRIPTION Other objects and advantages will become apparent in the ensuing specification and appended drawing, wherein;

FIG. 1 is a longitudinal view of a pump embodying the invention, the housing thereof being shown in section and the rotor in elevation, with the slipper vanes shown on one side only;

FIG. 2 is a cross-sectional view of the same taken as indicated by line 22 of FIG. 3, with major portions of the housing shell and rotor shown in end elevation;

FIG. 3 is a longitudinal sectional view of the same, taken as indicated by line 33 of FIG. 2, one side of the rotor being shown with a slipper vane assembled therein (one end thereof broken away) and the other side being shown with its vane omitted;

FIG. 4 is a detailed sectional view of a slipper vane on an enlarged scale.

Referring now to the drawing in detail, I have shown therein, as an example of one form in which the invention may be embodied, a rotary vane hydraulic pump comprising, in general, a housing A, a rotor body B cooperating with an internal cam surface of the housing to define a pair of diametrically opposed pumping chambers C; a drive shaft D; a plurality of vane assemblies E which are retained in respective sockets in rotor body B in which they are slidable radially to follow the interior cam surface of housing A; inlet ducting I and outlet ducting (shown schematically) both communication with respective pumping chambers to carry fluid to inlet sides of the chambers and deliver fluid from the outlet sides of the chambers.

Housing A comprises a cylinder shell 7 of oval cross section and respective end closures 8 and 9, at least one of which is removable for assembly purposes and is attached and sealed to the respective end of shell 7 by any well-known means. The periphery of rotor body B embodies a succession of arcuate surfaces (interrupted by vane sockets) which collectively define a cylindrical surface generated from its axis of rotation, as is common in rotary vane pumps. The internal cam surface of cylinder shell 7 is of oval cross section, embodying diametrical opposed outwardly arched areas 10 which are spaced from the cylindrical rotor periphery; dwell areas 12 centered at between the areas 10, of nearly cylindrical curvature conforming substantially to the rotor periphery; and eccentric, circumferentially pitched transition areas 13 extending between the areas 10 and 12 and tangent to both. Areas 10, each extending from an inlet to a respective outlet, may be of approximately 36 circumferential extent. Transition areas 13 are approximately 50-54 in circumferential extent.

For a rotor having a diameter of about 1.3 inches, the dwell areas 12 may have a clearance of the order of 0.010 inch from the periphery of rotor body B. These close-fitting areas 12 may have a circumferential arc length of about 36 each. Between the areas 10 and 13 and the rotor periphery are defined the pumping chambers C which are crescent-shaped circumferentially. At or near the centers of areas 10, chambers C have a maximum radial depth which may be about 0.080 inches. Vanes E may be nine in number and 40 apart, and have a circumferential extent of sealing contact with the cylinder wall area 10 such that at least one vane will seal off the inlet of each chamber C from its outlet at all times.

The rotor body B comprises a hub annulus 20 (FIG. 3) having an axial shaft bore 21 with internal splines 22 to which shaft D is coupled; an intermediate annular array of segments 23 separated circumferentially by axially extending radial vane slots 24 having enlarged root chambers 25 in the form of cylindrical bores extending axially from end to end of the rotor body; and narrowed spokes 26 projecting radially from respective segments 23 and extending full length of the rotor body B, parallel to its axis. Each spoke 26 is formed with pairs of circumferentially opposed lateral notches 27 and 28 at its ends and intermediate its ends respectively. Between each pair of notches is a relatively thin web portion 29 of the respective spoke, the intervening body portions of each spoke being relatively thick, with arcuate tip faces 30 of maximum sealing area. The vanes E have corresponding portions, as will presently be described. The spokes 26 are circumferentially spaced to define between them longitudinally extending slipper sockets 31 in which are received the slipper portions of vanes E.

Vanes E are each composed of a valve consisting of a flat divider leaf 35 and an integral trunnion head 36 along its outer longitudinal margin; and a shoe or slipper 37 of bar fonn and of C crosssection circumferentially, having a longitudinal socket groove 38 in which bead 36 is pivotally coupled. Slipper 37 (FIGS. 1 and 4) has pairs of notches 39 registering with notches 27 and 28 of spokes 26. Between the notches 39 are thick body portions having circumferentially broad tip surfaces 40 corresponding to the broad tip areas 30 of spokes 26, and having arcuate sides 41 which are mainly of segmental cylindrical configuration concentric with the pivot axis of grooves 38. Sides 41 are received in slipper sockets 31 sufficiently closely to position the slipper against circumferential displacement yet sufficiently loosely to allow the slipper to freely tilt about its trunnion bead 36 as it rides against the transition areas 13 of the cylinder wall which areas have a cam slope with reference to the cylindrical periphery of the rotor.

Inlet ducting I, shown schematically in FIG. 2, may be of any suitable form to provide diametrically opposite inlets 50 to each of the pumping chambers C, each inlet 50 communicating with a plurality of inlet ports 51 in cylinder shell 7. The ports 51 are positioned to register with respective pockets which are defined by the lateral notches 27 and 28 of rotor spokes 26 and the registering notches 39 of slippers 37. Inlet ports 51 and outlet ports 52 extend circumferentially in shell 7 to an extent which may be about 54 for each port, as indicated in FIG. 2. They may be substantially coextensive with transition areas 13 circumferentially. The inlet ports 51 communicate with the ends (circumferential extremities) of pumping chambers C which the slippers 37 enter as they move from the dwell areas 12 to transition areas 13 of the cylinder, and corresponding outlet ports 52 are provided in the wall of cylinder shell 7,.in positions communicating with the ends of chambers C in which the slippers are disposed as they pass from the transition areas leading to the dwell areas 12 of the cylinder. The outlet ducting (shown schematically) includes diametrically opposed outlets 53 each communicating with the several ports 52 which in turn communicate with the respective pumping pockets 27, 28, 39. The inlet and outlet ducting l and 0 include respective common inlet and outlet connections 55, 56 and any suitable ducting from the common connections 55, 56 to their respective dual inlets 50 and 53, but such ducting may be of any selected'configuration to meet installation specifications and need not be the particular configuration shown in the drawing. The relative location of inlets 50 and outlets 53 is determined by the direction of rotation of rotor B. In the arrangement shown, the direction of rotation is as indicated by the arrow in FIG. 2.

OPERATION As the rotor revolves in response to rotation of drive shaft D, the slipper vanes E will be carried by rotor B around the oval cam surface of the cylinder shell 7. When travelling along the dwell areas 12, the vanes D will be withdrawn into their sockets 31, as shown at the top and bottom of FIG. 2. Under the pull of centrifugal force, the vanes B will move outwardly along the rising transition surfaces 13 as they travel from the close-fitting surfaces 12 to the outwardly arched areas 10. In these transition movements, as shown at the rightward side of FIG. 2, the slippers 37 will tilt around the trunnion beads 36 so as to maintain their peripheral surfaces 40 in balanced conforming contact with the transition areas 13, to maintain a good seal between the slipper and the cylinder surface. As the slipper moves into the pumping chamber C, it will move radially outwardly, displacing fluid from inlet port 51 into its respective socket 31 and into the opening space of chamber C. As the slipper approaches the center of an arched area it will tilt back to a position normal to the rotor radius bisecting it (as shown at the leftward side of FIG. 2) thus maintaining the conforming, sealing contact with the cylinder surface. At the same time, the vane ahead of it will have passed over and uncovered the outlet port 53 which is being approached, and the fluid ahead of the following slipper will be driven out through the port. The receding movement of a slipper into its socket as it is moved radially inwardly by camming action of a transition surface 13, will displace fluid from the socket into the outlet port 52.

The valves 35 function to provide radially reciprocating pivots on which the slippers 37 may tilt to follow the cam surface of the cylinder. While sliding radially they function as separator gates in the socket 31, preventing flow beneath the slippers 37 from their high pressure to their low-pressure sides. Although loosely fitted in its slot 24, a valve 35 will be moved by the pressure differential toward the low-pressure.

side of its socket 31 and the pressure in the high-pressure side will press it against the low pressure side of its slot 24, thus effecting a seal. For example, the vane shown in section at the leftward side of, FIG. 2 will develop a differential of relatively high pressure on its leading side while approaching outlet 52 and reducing the volume of the outlet portion of chamber C ahead of it, over relatively low pressure on its trailing side where the volume of the inlet portion of chamber C is increasing. By the time the slipper reaches a position covering an outlet port 52, as at the rightward side of FIG. 2, the suction on its trailing side will have subsided and the pressure differential across its valve will have dropped to zero, releasing the seal of valve leaf 35 against the trailing side of its slot. As the slipper advances, pressure will be built up on its trailing side by the action of the following slipper (moving past an inlet port 51) and a period of balanced pressure (across the slipper passing the outlet port) will occur during which the remaining fluid in the extremity of chamber C ahead of this slipper, will be vented around the inner margin of its valve leaf 35 through its slot 24 and root chamber 25 to the trailing side of the slipper. When this venting is completed, the pressure differential across the slipper will be reversed, with higher pressure on its trailing side and lower pressure on its leading side. Its valve leaf 35 will then be shifted into sealing contact with the leading side of its slot 24 so as to develop maximum discharge pressure in the portion of chamber C behind this slipper and aheadof the following slipper, which will then proceed to move the fluid ahead of it into the outlet port 52. The reversal of the valve and the venting during such reversal, avoids the entrapment of fluid in the remaining area of chamber C ahead of a slipper that has sealed off the outlet.

It will now be apparent that the valve leaf portion of each valve constitutes a divider leaf which normally separates the spaces in the two halves of a socket 31 beneath the slipper therein; and also constitutes a valve for venting one of these spaces (the leading one) into the other (the trailing one) during the interval of reversal of the pressure differential across the vane.

The tip surfaces 40 of slippers 37 have circumferential breadth such as to rest against cylinder surfaces 10, 12, 13 with sufficient seating engagement to control the tilting of the slippers so as to maintain maximum contact area at all times, thereby maintaining a seal of maximum effectiveness at all times, while minimizing wear. These tip surfaces are convexly rounded, of segmental cylindrical contour conforming substantially to the curvature of arched surfaces 10 (more closely than to either of the areas 12, 13) so as to make most complete contact with the surfaces 10 when substantial pressure differential across the slipper exists.

Substantial clearance between the sides of divider leaf 35 and slot 24 is provided. For example, where the thickness of leaf 35 is in the range of 0.028 to 0.030 inch, the slot may have a width in the range of 0.035 to 0.037 inch with an aggregate clearance of 0.007 inch for free radial sliding and for valving and flow passage for fluid to move in and out of chamber 25.

The lateral walls of slipper sockets 31 are parallel to one another and to a plane of the rotor axis passing through the socket (preferably the medial plane of the socket). Thus the slipper 37 may move radially in the socket while the clearance between its lateral faces and the socket walls remains unchanged, the clearance being such that the socket walls embrace the sides of the slipper to position it at all times against circumferential displacement while permitting free radial movement of the slipper.

It may be noted that the circumferential width of slippers 37 and sockets 31 is substantially equal to the arcuate width of the tip surfaces 30 of spokes 26 (e.g., each being approximately 20).

Shaft D may extend through and be rotatably supported in bearings (e.g. carbon bushings) 15 mounted in bosses in the respective end closures 8 and 9.

I claim:

1. A vane-type rotary fluid pump comprising:

a rotor including a plurality of spokes having accurate tip surfaces collectively defining a generally cylindrical P p y;

a housing in which said rotor is mounted for rotation, including a cylinder shell having an internal cam surface including an area closely conforming to said rotor periphery, an outwardly arched portion defining with said periphery a pumping chamber of crescent shape circumferentially, and an intervening transition area of pitched eccentricity;

said spokes being shaped to define, between adjacent spokes, sockets and radial slots at the bottoms of said sockets;

longitudinally extending peripheral slipper and a plurality of pumping vanes each including a divider leaf extending longitudinally in a respective slot and separating the leading area from the trailing area thereof; and

a slipper of bar form pivotally linked to the outer margin of 5 said divider leaf, said slipper having longitudinally spaced notches and intervening thick portions having circumferentially broad tip surfaces for balanced seating and low-wear sliding bearing engagement with said cam surface and for circumferential tilting to follow said cam surface while conforming to pitch inclination thereof;

said slipper and leaf being slidable radially in their respective socket and slot whereby said vanes will move radially to maintain contact with said cam surface;

said housing having respective inlet and outlet ports communicating with said pumping chamber at circumferentially spaced positions.

2. A pump as defined in claim 1; said divider leaf having a longitudinal trunnion bead along its outer margin, and said slipper having a longitudinal socket groove receiving said bead to provide a pivotal coupling connection between said leaf and slipper.

3. A pump as defined in claim 1, wherein said inlet and outlet ports are positioned in the planes of rotation of said notches.

4. A pump as defined in claim 3, wherein said rotor spokes have respective longitudinally spaced notches registering with said slipper notches to define therewith pockets communicating with said inlet and outlet ports as the rotor revolves.

5. A pump as defined in claim 1, wherein the axis of pivotal linking of said slipper to said leaf is substantially coaxial with the cross-sectional center of said slipper and said slipper has lateral surfaces of segmental cylindrical contour substantially coaxial with said axis.

6. A pump as defined in claim 5, wherein said slipper sockets have lateral walls which are in embracing relation to said lateral slipper surfaces sufficiently closely to position the slipper against substantial circumferential displacement but with sufficient clearance to allow free tilting, said lateral walls being disposed on opposite sides of a plane of the rotor axis and parallel thereto so to allow free radial movements of the slipper.

7. A pump as defined in claim I, wherein said slippers have broad tip surfaces convexly rounded to conform generally to the curvature of said cam surface of the shell, for said lowwear bearing engagement therewith coupled with maximum sealing action.

8. A pump as defined in claim 7, wherein the convex curvature of said tip surfaces is conformed more closely to the curvature of said outwardly arched portion of said cam surface than to other areas thereof.

9. A pump as defined in claim 1, wherein said divider leaf is loosely received in said slot with clearance such that it will be sealed to one side of its slot when a differential of pressure is exerted on its side opposite said one side of its slot, and will be shifted laterally and be sealed against the other side of its slot when pressure differential is reversed so as to be applied against its other side.

10. A pump as defined in claim 9, wherein said clearance is such that said leaf will function as a valve to vent fluid from its leading side through said slot and around its inner margin to its trailing side when its slipper has passed a discharge port, thereby avoiding entrapment of fluid in the remainder of the pumping chamber ahead of the slipper.

11. A pump as defined in claim 1, wherein said slippers are spaced apart circumferentially substantially 40 and said inlet and discharge ports are spaced apart substantially 36.

12. A pump as defined in claim 11, wherein said slippers, slipper sockets and spokes have substantially equal maximum widths circumferentially. 

1. A vane-type rotary fluid pump comprising: a rotor including a plurality of spokes having accurate tip surfaces collectively defining a generally cylindrical periphery; a housing in which said rotor is mounted for rotation, including a cylinder shell having an internal cam surface including an area closely conforming to said rotor periphery, an outwardly arched portion defining with said periphery a pumping chamber of crescent shape circumferentially, and an intervening transition area of pitched eccentricity; said spokes being shaped to define, between adjacent spokes, longitudinally extending peripheral slipper sockets and radial slots at the bottoms of said sockets; and a plurality of pumping vanes each including a divider leaf extending longitudinally in a respective slot and separating the leading area from the trailing area thereof; and a slipper of bar form pivotally linked to the outer margin of said divider leaf, said slipper having longitudinally spaced notches and intervening thick portions having circumferentially broad tip surfaces for balanced seating and low-wear sliding bearing engagement with said cam surface and for circumferential tilting to follow said cam surface while conforming to pitch inclination thereof; said slipper and leaf being slidable radially in their respective socket and slot whereby said vanes will move radially to maintain contact with said cam surface; said housing having respective inlet and outlet ports communicating with said pumping chamber at circumferentially spaced positions.
 2. A pump as defined in claim 1; said divider leaf having a longitudinal trunnion bead along its outer margin, and said slipper having a longitudinal socket groove receiving said bead to provide a pivotal coupling connection between said leaf and slipper.
 3. A pump as defined in claim 1, wherein said inlet and outlet ports are positioned in the planes of rotation of said notches.
 4. A pump as defined in claim 3, wherein said rotor spokes have respective longitudinally spaced notches registering with said slipper notches to define therewith pockets communicating with said inlet and outlet ports as the rotor revolves.
 5. A pump as defined in claim 1, wherein the axis of pivotal linking of said slipper to said leaf is substantially coaxial with the cross-sectional center of said slipper and said slipper has lateral surfaces of segmental cylindrical contour substantially coaxial with said axis.
 6. A pump as defined in claim 5, wherein said slipper sockets have lateral walls which are in embracing relation to said lateral slipper surfaces sufficiently closely to position the slipper against substantial circumferential displacement but with sufficient clearance to allow free tilting, said lateral walls being disposed on opposite sides of a plane of the rotor axis and parallel thereto so to allow free radial movements of the slipper.
 7. A pump as defined in claim 1, wherein said slippers have broad tip surfaces convexly rounded to conform generally to the curvature of said cam surface of the shell, for said low-wear bearing engagement therewith coupled with maximum sealing action.
 8. A pump as defined in claim 7, wherein tHe convex curvature of said tip surfaces is conformed more closely to the curvature of said outwardly arched portion of said cam surface than to other areas thereof.
 9. A pump as defined in claim 1, wherein said divider leaf is loosely received in said slot with clearance such that it will be sealed to one side of its slot when a differential of pressure is exerted on its side opposite said one side of its slot, and will be shifted laterally and be sealed against the other side of its slot when pressure differential is reversed so as to be applied against its other side.
 10. A pump as defined in claim 9, wherein said clearance is such that said leaf will function as a valve to vent fluid from its leading side through said slot and around its inner margin to its trailing side when its slipper has passed a discharge port, thereby avoiding entrapment of fluid in the remainder of the pumping chamber ahead of the slipper.
 11. A pump as defined in claim 1, wherein said slippers are spaced apart circumferentially substantially 40* and said inlet and discharge ports are spaced apart substantially 36*.
 12. A pump as defined in claim 11, wherein said slippers, slipper sockets and spokes have substantially equal maximum widths circumferentially. 